The correct answer is C. Plasmodium.
Malaria is a disease caused by a parasite called Plasmodium. The parasite is spread to people through the bite of an infected Anopheles mosquito. Once inside the human body, the parasite attacks red blood cells, causing fever, chills, and other symptoms. Malaria can be a serious disease, and can even be fatal.
Bacteria are single-celled organisms that can cause a variety of diseases, including pneumonia, tuberculosis, and strep throat. Fungi are multicellular organisms that can cause diseases such as athlete’s foot, ringworm, and yeast infections. Viruses are even smaller than bacteria, and they can cause a variety of diseases, including the common cold, the flu, and HIV/AIDS.
While bacteria, fungi, and viruses can all cause disease, Plasmodium is the only one that causes malaria.